Water is becoming one of the most precious natural resources in arid areas of the world. Meeting future water needs in these arid areas may require aggressive conservation measures. This in turn requires irrigation systems that apply water to the landscape based on the water requirements of plants in that particular landscape.
Many automatic irrigation controllers are known. They range from simple devices that control watering times based upon fixed schedules, to sophisticated devices that vary the watering schedules according to local geography and climatic conditions.
With respect to the simpler types of irrigation controllers, a homeowner typically sets a watering schedule that involves specific run times and specific days for each watering station. With these simple types of controller systems, the controller executes the same schedule regardless of change of seasons or weather conditions. Typically, the homeowner would manually adjust the watering schedule, but only a few times during the year. The adjustments are generally based on the homeowner's perceptions rather than the actual watering needs of the landscape. One manual adjustment is typically made in late Spring, when a portion of the yard becomes brown due to a lack of water. Another manual adjustment is typically made in late Fall, when the homeowner assumes that vegetation does not require as much watering. These manual adjustments to the watering schedule are typically insufficient to achieve efficient watering. Further, such controllers do not provide feedbacks to homeowners with respect to the efficiency of their watering practices.
More sophisticated irrigation controllers use evapotranspiration rates to determine the amount of water needed for a landscape. Evapotranspiration (ETo) is the process whereby water is discharged into the atmosphere by direct evaporation from the soil and the plant, and by transpiration from the plant's surface. Irrigation controllers that derive all or part of the irrigation schedule from ETo data (ET irrigation controllers) are discussed in U.S. Pat. No. 5,479,339, issued December 1995, to Miller, U.S. Pat. No. 5,097,861, issued March 1992 to Hopkins, et al., U.S. Pat. No. 5,023,787, issued June 1991, and U.S. Pat. No. 5,229,937, issued July 1993, both to Evelyn-Veere, U.S. Pat. No. 5,208,855, issued May 1993, to Marian, U.S. Pat. No. 5,696,671, issued December 1997, and U.S. Pat. No. 5,870,302, issued February 1999, both to Oliver, and U.S. Pat. No. 6,102,061, issued August, 2000, U.S. Pat. No. 6,227,220, issued May, 2001, U.S. Pat. No. 6,298,285, issued October, 2001, U.S. Pat. No. 6,892,113, issued May, 2005, U.S. Pat. No. 6,892,114, issued May, 2005, U.S. Pat. No. 6,944,523, issued September, 2005, U.S. Pat. No. 6,947,811, issued September, 2005 and U.S. Pat. No. 6,950,728, issued September, 2005, all to Addink, all of which are hereby incorporated by reference in their entirety.
Even with these ET irrigation controllers, the consumer will generally modify the irrigation schedule such that it's different from scheduled amounts that were based on ETo. For example, a consumer typically makes adjustment to increase irrigation amount when he sees a dry spot on the landscape, and forgets to change the controller setting back to the original setting when such increase is no longer needed. A modification of the irrigation system to improve distribution uniformity might have corrected the dry spot problem without requiring the consumer to change the controller setting. Also, ET controllers do not provide feedbacks to homeowners with respect to the efficiency of their watering practices.
What is required is a method whereby the irrigation controller automatically modify future run-times to consistently irrigate the landscape based on the amount of water that should be applied to the landscape, based on ETo information.
All referenced patents, applications and literatures are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.